1. Field of the Invention
The present invention relates to a receiving apparatus that receives transmission data wirelessly transmitted from a capsule endoscope introduced into an inside of a subject, and relates to a capsule endoscope system.
2. Description of the Related Art
Conventionally, a technique of receiving, by a receiving apparatus attached on an outside of a subject, image data which is captured by and wirelessly transmitted from a capsule endoscope that is inserted into the subject and captures images of an inside of the subject has been known (see Japanese Patent Application Laid-Open No. 2007-88860, for example).
A capsule endoscope transmits transmission data frame by frame at a specified frame rate. The transmission data is serial data including a preamble embedded at a head part and image data captured by the capsule endoscope.
The receiving apparatus includes a plurality of receiving antennas attached on a surface of a body of the subject. The receiving apparatus selects, after detecting the preamble of the transmission data, a receiving antenna whose received power is the largest of the plurality of receiving antennas. After that, the receiving apparatus detects a vertical synchronization signal included in the image data to start to receive the image data.
When the receiving apparatus is in an initial condition where transmission data is not received from the capsule endoscope or in a defect condition where transmission data is not received for a specified period of time after the latest reception, the receiving apparatus performs, after selecting a receiving antenna whose received power is the largest, a detection of the preamble included in the transmission data. When the preamble cannot be detected even after a lapse of a specified period of time after the selection of the receiving antenna, the receiving apparatus selects a receiving antenna again and then performs the preamble detection again. In this manner, the conventional receiving apparatus repeats the receiving antenna selection and the preamble detection until receiving transmission data when the receiving apparatus is in the initial condition or in the defect condition. In the receiving apparatus having such a configuration as explained above, it is possible to surely receive transmission data from the capsule endoscope.